The invention relates to a method of manufacturing a semiconductor device whereby a capacitor is provided on a surface of a semiconductor body comprising a semiconductor element in that consecutively a lower electrode, an oxidic ferroelectric dielectric, and an upper electrode are provided in such a way that the upper electrode does not cover an edge of the dielectric, after which an insulating layer with superimposed metal conductor tracks is provided. The invention also relates to a semiconductor device comprising a capacitor with a ferroelectric dielectric.
Such a method is suitable for manufacturing a semiconductor device which can operate, for example, as an electronic memory in a computer. The semiconductor body then comprises very many semiconductor elements and capacitors. Capacitors having a ferroelectric material as a dielectric form non-volatile memory elements. When an electric field is applied across a ferroelectric material and removed again, a permanent polarization of the material remains, depending on a direction of the electric field, i.e. the ferroelectric material remembers the direction of the electric field. Especially oxidic materials such as, for example, lead titanate, lead-lanthanum titanate, and lead-lanthanum-zirconium titanate exhibit ferroelectric properties.
European Patent Application 91200525.3 (PHN 13.274) discloses a method of the kind mentioned in the opening paragraph whereby a capacitor with a lower electrode comprising platinum, a ferroelectric dielectric, and an upper electrode comprising platinum are provided on a semiconductor body. Lead-zirconium titanate is used as the ferroelectric dielectric in that case. The semiconductor body also comprises a switching transistor which is connected to the capacitor by a metal conductor track of TiW and Al which is provided over an insulating layer of silicon oxide.
It is found in practice that a device manufactured by the known method described is comparatively slow and, for example, shows an access time which is longer than 100 nsec.